M. Liao

Structure and electrical properties of Bi3.15Nd0.85Ti3O12 nanofibers synthesized by electrospinning and sol-gel method

Bi3.15Nd0.85Ti3O12 (BNT) nanofibers with radii in the range of 30–200 nm have been prepared by the electrospinning and sol-gel method, and the structure and morphology of the nanofibers were characterize by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The phase transition and piezoelectric characteristics of the BNT nanofibers were performed by thermal analysis and scanning probe microscopy, respectively. The BNT nanofiber exhibits an effective piezoelectric coefficient of 89 pm/V and a Curie temperature of 500 °C, which are higher than that of the BNT bulk.

Ferroelectric and dielectric properties of Nd3+∕Zr4+ cosubstituted Bi4Ti3O12 thin films

Thin films of Nd3+∕Zr4+ cosubstituted Bi4Ti3O12 (BIT), i.e., Bi3.15Nd0.85Ti2.8Zr0.2O12 (BNTZ), were fabricated on Pt∕Ti∕SiO2∕Si(100) substrates by chemical solution deposition and annealed at different temperatures of 600, 650, 700, and 800°C. The effects of annealing temperature on the microstructure, leakage current, ferroelectric, and dielectric properties of the BNTZ films were investigated in detail. Significantly, compared with the Bi3.15Nd0.85Ti3O12 film, the BNTZ thin film has a lower coercive field (2Ec) and leakage current density and a slightly larger remnant polarization (2Pr). It shows that Nd3+∕Zr4+ cosubstitution in BIT film might be an effective way to improve ferroelectric properties of BIT.

COMPARISON OF FERROELECTRIC PROPERTIES OF COSUBSTITUTED BISMUTH TITANATE FILMS BETWEEN Bi3.15Nd0.85Ti2.97Mg0.03O12 AND Bi3.15Nd0.85Ti2.95Mn0.05O12

Aiming at the influence of substitution on ferroelectric behaviors, Nd and Mg/Mn cosubstituted bismuth titanate films, Bi3.15Nd0.85Ti2.97Mg0.03O12 (BNTMg) and Bi3.15Nd0.85Ti2.95Mn0.05O12 (BNTMn), have been prepared on Pt/Ti/SiO2/Si(100) substrates at 700°C by a chemical solution deposition technique, respectively. A series of comparisons including structures, surface morphologies, and ferroelectric properties of the as-prepared films were carried out by X-ray diffraction, scanning electron microscope, and a Radiant Technologies Precision Workstation for ferroelectric test system. It was found that the films possess preferred the (117) and (00l)-oriented polycrystalline structures, and the remnant polarization of BNTMg film is larger than that of BNTMn film and the coercive field of BNTMn film is lower than that of BNTMg film. The values of 2Pr and 2Ec of BNTMg and BNTMn are 28 μC/cm2 and 212 kV/cm, and 15 μC/cm2 and 175 kV/cm, respectively. The relevant physical mechanisms were pursued.

An ultrathin flexible electronic device based on the tunneling effect: a flexible ferroelectric tunnel junction

Flexible electronics have attracted long-standing attention in todays energy-conscious world. Among the flexible electronics, the flexible ferroelectric tunnel junction can realize non-destructive readout and consume less energy, and it may be a very promising device owing to the advantages of excellent portability, bendability and being lightweight. However, few flexible ferroelectric tunnel junctions with good performance have been reported because the inorganic materials with good ferroelectric properties always have a high crystallization temperature, which restricts the flexible substrate selection. In this report, we report a flexible ferroelectric tunnel junction that is based on PbZr0.52Ti0.48O3 film grown on mica with a bottom electrode of SrRuO3 film. The flexible ferroelectric tunnel junction of asymmetric structure not only can achieve nondestructive readout, but it also has good bendability. Especially, the on/off ratio of the junction averages about 1.08 × 104%. The application of flexible ultrathin ferroelectric film is beneficial to realize flexible ferroelectric electronic devices that are integrated with flexible circuit systems in modern microelectronics.